Insect Pests of Bamboos in Asia INBAR ■ Other Aphids Chucallis bambusicola Tak., Pseudoregma albostriata Liao, P. alexanderi Tak. and P. koshunensis Tak. are found on shoots of Miscentus sp., Sinocalamus oldhami and Dendrocalamus latiflorus, but in low numbers and cause only minor damage. Other common aphids include Astegopteryx insularis van der Goot, Takecallis arundinariae Essig., T. taiwanus Tak., Melanaphis bambusae Full., Pseudoregma bambusicola Tak. and Ceratovacuna spp. which occur in China, Indonesia, Japan and Malaysia. All these species feed on the back side of leaves and are capable of causing considerable damage. P. bambusicola,for instance, feeds on sap from bamboo culms and tips, causing reduction in vigour. Pseudococcid Scale Insects (Homoptera: Pseudococcidae) More than 150 species of scale insects belonging to the families Aclerdidae, Margarodidae, Pseudococcidae, Asterolecaniidae and Diaspididae have been reported as pests on bamboos in Asia (Yan Aojin 1985; Wang Ziqing and Zhang XJ 1987; Wu Shijun 1992; Xu Tiansen et al. 1993). The sap-sucking scale insects are tiny, with their bodies covered in a waxy covering (theca). The wingless female adults and nymphs feed by inserting minute suckers into plant tissues and sucking the sap. Eggs are laid in large clusters beneath the female’s waxy layer, and the nymphs crawl out after hatching. Male adults, which are winged, survive only for a few days. These scale insects usually secrete a great deal of honeydew, and the damaged bamboo (leaves, branches and culms) shows a blackened appearance because of the sooty mould fungus that 79 grows on this secretion. INBAR Insect Pests of Bamboos in Asia About 40 species of pseudococcid scale species have been reported as sap suckers on foliage, branches or culms of various bamboos. Some of these species are quite abundant in bamboo stands and cause a general reduction in growing vigour and even the death of bamboo plants. ■ Nesticoccus sinensis Tang DISTRIBUTION China. HOSTS Phyllostachys spp. and Arundinaria spp. Fig. 34: Nesticoccus sinensis a: 1st nymph instar in its waxy covering; b: male adult BIOLOGY The pear-shaped female adults are 2.2-3.3 mm long and brownish in colour, but are covered with a greyish, waxy covering. There is only one generation per year. Female adult sucks sap from leaf sheaths from June to 80 the following May. Nymphs, which also have the waxy Insect Pests of Bamboos in Asia INBAR covering (see Fig. 34a), pass through three instars in 6-7, 15-22 and 10 days, respectively, in May-June, and cause the same damage as female adults. CONTROL About 20-50% of the insect is parasitized by encyrtid wasps (Xie Guolin 1983). ■ Eriococcus rugosus Wang DISTRIBUTION Central China. HOST Phyllostachys pubescens. BIOLOGY The egg-shaped female adults are 3.1 mm long and covered with a white, waxy covering. There is one generation per year. Sap-sucking goes on throughout the year, with nymphs feeding on leaf sheaths and female adults preferring twigs (Zhang Guoxian et al. 1992). ■ Other Pseudococcid Scale Insects Antonina crawii Cockerell is widespread in all bamboo-growing areas in China. Both female adults and nymphs suck sap from leaf sheaths throughout the year. Two generations occur per year. The female adult, including its white, outer waxy covering, measures about 2.7 mm long and 1.9 mm wide (Xu Ji 1983). Other common species in this family include Eriococcus transversus Green, Antonina indica Green, 81 INBAR Insect Pests of Bamboos in Asia A. pretiosa Ferris, A. zonata Green, Chaetococcus bambusae Maskell, Trionymus pulverarius Newst. var. bambusae Green, Heliococcus bambusaniae Wang and Kiritshenkella magnotubulata Borchs. These are found attacking Phyllostachys, Bambusa, Dendrocalamus and Sinocalamus species in China, India, Japan, Sri Lanka, and some Southeast Asian countries. A NOTE ON CONTROL OF PSEUDOCOCCID SCALE INSECTS Spraying 0.04% water solution of dimethoate on young nymphs, and injecting 50% methamidophos at the rate of 1.5 ml per culm to control adult females are effective measures (Hu Heyuan and Min ZJ 1988; Zhang Guoxian et al. 1992). Pit Scale Insects (Homoptera: Asterolecaniidae) Pit scale insects are very common on bamboos. There are over 50 species in this group, mostly classified to genera Asterolecanium and Bambusaspis, but only a few of them can be considered important. ■ Asterolecanium bambusae Boisduval DISTRIBUTION China, India and the Philippines (Dayan 1990). HOST Bambusa vulgaris. BIOLOGY AND CONTROL The scale insect feeds on the sap from culm sheath and 82 forms clusters on the stems. Because of the glassy wax Insect Pests of Bamboos in Asia INBAR covering on mature females, and subsequently on eggs, chemical control is difficult. Singh and Bhandari (1988) recorded a coccinelid, Cryptolacmus sp., as an effective predator on the scale. Systemic insecticides such as dimethoate has also been recommended (Hamon 1980). There are several other species of the genus Asterolecanium — such as A. delicatum Green, A. flavoaliatum Green, A. coronatum Green, A. lanceolatum Green and A. logum Green — reported as infesting various parts of Bambusa and Dendrocalamus species. Other recorded species include A. pudibundum Green, A. soleonophoides Green, A. rubronumatum Green and A. udagammae Green. None of these are known to be of economic significance. ■ Bambusaspis hemisphaerica Kuwana DISTRIBUTION China and Japan. HOSTS Phyllostachys spp., Bambusa metake and Arundinaria chino. BIOLOGY The female adult is characterized by the semiglobose, waxy covering, which is 2.5-3 mm long and greenish- yellow in colour. The scale occurs in 1-2 generations per year, and causes damage through female adults and nymphs which suck sap from twigs and leafstalks (Yan Aojin 1992). 83 INBAR Insect Pests of Bamboos in Asia ■ Other Pit Scale Insects Bambusaspis bambusae Boisduval, B. masuii Kuwana and B. miliaris Boisduval cause similar damage on Bambusa hemisphaerica in China, Japan, India, Sri Lanka and the Philippines. Armoured Scale Insects (Homoptera: Diaspididae) About 60 species of armoured scale insects have been found on various bamboos, and some of them are considered important with regard to the damage they cause to bamboo culms and leaves. ■ Kuwanaspis pseudoleucaspis Kuwana DISTRIBUTION China, Japan and Korea. Fig. 35: Kuwanaspis pseudoleucaspis 84 on bamboo culm Insect Pests of Bamboos in Asia INBAR HOST Phyllostachys spp. BIOLOGY The female adult, along with its waxy covering, is 1.1-3 mm long, 0.4-0.8 mm wide and white in colour. There are two generations per year. Both nymphs and female adults feed in groups on culm sap from June to the following April. In severe outbreaks, the culm shows a white appearance because of the large number of scales present, and become commercially valueless. There is also a general reduction in the growth vigour of the stands. CONTROL About 21% and 60% of adult females in the two generations, respectively, are parasitized by a chalcid wasp (Hymenoptera: Encyrtidae). The ladybird beetles Chilocorus kuwanae Silvestri and Telsimia sp. prey on eggs and newly-hatched nymphs (Yang Mingzhen et al. 1984; Yan Aojin et al. 1985). Kuwanaspis howarai Cooley usually occurs together with K. pseudoleucaspis, and has similar life cycle and damaging habits. The ladybird beetle Chilocorus kuwanae feeds on this scale also (Feng Zongxuan et al. 1987). ■ Unachionaspis bambusae Cockerell DISTRIBUTION China. HOST Phyllostachys spp. 85 INBAR Insect Pests of Bamboos in Asia BIOLOGY This scale insect found on bamboo leaves has three generations per year. The pear-shaped, waxy covering of female adults is 1.8-2.5 mm long and white in colour. The pest prefers feeding on young leaves in the lower crown, and a heavy attack can cause defoliation. CONTROL About 15-30% of the scale is parasitized by Aphytis chrysomphali Mercet, and 5-10% preyed upon by the ladybird beetle Telsimia sp. (Wu Shijun 1981). ■ Other Armoured Scale Insects Several species in the genus Odonaspis — such as O. canaliculatus Green, O. penicillata Green, and O. inusittatus Green, O. senireta Cockerell, O. simplex Green and O. elongata — are reported on Phyllostachys spp. and Bambusa vulgaris in China and India. In India, several of these are found to infest leaf petioles and the basal part of leaf sheaths of B. vulgaris. But they are pests of minor economic importance. O. penicillata occurs one generation per year in China and causes damage through nymphs and female adults which suck sap from culms and branches. Adults emerge in late June or early July and overwinters on bamboo plants. The armoured scale insects found on leaves are mostly classified to the genera Unachionaspis,Chionaspis and Greenaspis, such as U. signata Maskall, C. bambusae Cockerell, C. arundinaria Green, C. spiculata Green, G. elongata Green and G. bambusifoliae Takahashi. A NOTE ON CONTROL OF ARMOURED SCALE INSECTS Almost all armoured scale insects, especially those 86 found on culms, prefer to feed on old plants and favour Insect Pests of Bamboos in Asia INBAR wet, shaded sites. Heavy attacks usually occur in dense, over-mature stands. Prevention of these conditions through silvicultural measures, such as reasonable and selective thinning, is effective and primary for the suppression of the insects. Various natural enemies, mainly chalcid wasps and ladybird beetles, play an important role in controlling the insects and should be properly protected. Because of the waxy covering of the nymphs and female adults, chemical control is not very feasible. However, spraying 0.05% water solution of malathion is recommended for controlling those species feeding on culms (Feng Zonxuan et al. 1987), while culm-cavity injection of systemic insecticides can be employed against outbreaks of scales feeding on leaves (Zhang Guoxian et al. 1992). White Flies (Homoptera: Aleyrodidae) Many species of white flies complete their life-cycle on bamboo, but none of them are reported as serious pests. ■ Aleurocanthus arundinacea Lamb DISTRIBUTION India. HOST Bambusa bambos. BIOLOGY This white fly feeds on leaf sap and lays eggs on leaves.